Vehicle License Plate Recognition Based on Hierarchical Approach

In order to accurately detect the various sizes of vehicle license plates which are included in input image, we introduce hierarchical approach and overlapped partitioning technique in this paper. The proposed approach firstly attempts the license plate detection for entire image. If detection is failed, the image is partitioned into 3 overlapped rectangular areas and the license plate detection is attempted again. If detection is failed again, the image is partitioned into 7 overlapped rectangular areas and license plate detection is attempted. The method to use for detecting license plate in each step is the edge-based projection technique.